The present invention relates to a through conductor such as a through electrode which penetrates a silicon substrate such as a package substrate with a semiconductor chip mounted thereon, a chip substrate of the semiconductor chip or the like and electrically connects the front and back sides of the silicon substrate, and a method for manufacturing the through conductor.
As a conventional through electrode, e.g., a through electrode provided in its corresponding semiconductor chip employed in a semiconductor package in which a plurality of semiconductor chips are laminated, there is formed a through electrode of a silicon (Si) substrate such as a wafer used as a chip substrate of the semiconductor chip, which is characterized by forming a mask pattern in a region excluding a region for forming the through electrode, etching the silicon substrate exposed by dry etching to form an electrode forming hole with a bottom, covering the bottom face and side face of the electrode forming hole with an insulating film comprised of silicon dioxide (SiO2) by a CVD (Chemical Vapor Deposition) method, thereafter forming a seed film by sputter, the CVD method or the like, embedding a conductor formed of a metal having conductivity into the electrode forming hole by a plating method or the like, and thereafter polishing the lower surface of the silicon substrate to expose the conductor to the bottom face of the electrode forming hole, thereby penetrating from an upper surface of the silicon substrate to its lower surface so as to electrically connect the upper surface side and the lower surface side (refer to, for example, a patent document 1 (Japanese Unexamined Patent Publication No. Hei 10 (1998)-223833 (paragraph 0061 in page 6-paragraph 0082 in page 7, FIG. 4 and FIG. 5)).
However, the above prior art has problems in that since the through electrode is formed as a circular cylinder which penetrates from the upper surface of the silicon substrate to the lower surface thereof, an electrolytic solution is hard to enter the electrode forming hole upon embedding of the conductor by an electrolytic plating method or the like when the aspect ratio (ratio between the diameter of hole and its depth) of its through electrode hole exceeds 10, and the mouth of the electrode forming hole is first blocked off, thereby causing the difficulty of filling the electrode forming hole with the conductor.